Bloodshot Eyes After Drinking: Side Effect Explained

bloodshot eyes after drinking

A common side effect the night after drinking is the appearance of conjunctivitis, or what is also known as having bloodshot eyes. This primarily takes the form of a red tint encompassing most of the sclera surrounding the pupil, as well as the inflammation and swelling of any small veins contained therein.

In certain situations, bloodshot eyes after drinking may even take the form of pupils being dilated to a certain degree, as well as discoloration or darkening of the skin surrounding the eyes, such as that of eyebags.

This can be due to a multitude of factors all condensing in the hours after the body has processed a significant volume of ethanol alcohol, and, while unsightly and somewhat difficult to avoid, may be reduced or cured through the use of several techniques and handy biological tricks.

Drinking Alcohol, Bloodshot Eyes and Vasodilation

The term vasodilation refers to a substance’s ability to enlarge or otherwise swell up the circulatory bodies throughout the human cardiovascular system – in layman’s terms, vasodilation means that the veins and arteries get bigger when one imbibes or otherwise absorbs a certain substance.

Alcohol in this particular case acts in a curious way, possessing both vasodilator and vasoconstrictor (the opposite) related effects depending on the individual’s own tolerance and how much alcohol they have consumed within a certain period of time.

While this may initially seem unrelated to the red hue of the drinker’s eyes the day after an evening at the bar, it is in fact the primary reason behind such a coloring, with the many smaller veins in the sclera or white of the individual’s eye becoming engorged from alcohol’s vasodilative properties alongside several other factors.

At a moderate level of consumption, alcohol’s vasoconstrictive properties are at its weakest and its vasodilative properties are at their peak, with the contraction or relaxation of the veins not only constrained to the eyes but throughout most of the body – hence the advice to never drink alcohol while at risk of frostbite.

The vasodilative effects accrued from alcohol consumption are not the only factor that lead to bloodshot eyes during and after a session of drinking, however, and as such simply counteracting the dilation of the vascular bodies may not be sufficient to get rid of the drinker’s reddened eyes.

Alcohol, Diuresis and Bloodshot eyes


Diuresis is the pronounced effect of the human body producing excessive amounts of urine due to the need to excrete a certain substance being processed by the kidneys and liver.

In regards to alcohol and its ability to induce bloodshot eyes in the drinker both during and after a session of drinking, diuresis can play quite a significant role, especially if the alcoholic drink in question is rather high in ABV and not mixed with other, non-alcoholic fluids.

This is due to the fact that alcohol is primarily eliminated through the hepatic system, with only two to five percent of the ethanol being excreted through sweat or exhalation.

This particular type of elimination often requires significant volumes of fluid, not only to shuttle the now altered ethanol alcohol away from the liver but also to excrete it from the body by transporting it to the appropriate elimination area.

This significant increase in fluid usage by the body can translate to a deficit in fluid usage in other organs, one of which are the eyes themselves.

Dehydration and the subsequent reduction in the drinker’s ability to produce lacrimal fluid – or tear fluid – can cause the eyes to become inflamed and irritated as the friction between the eyelid and the sclera is increased, as well as passive evaporation affecting the surface of the eye itself.

While this particular side effect of alcohol is theoretically avoidable by either consuming a glass of water with every standard alcoholic drink the individual will imbibe or only consuming low proof alcohol with a high volume of additional non-alcoholic fluid, it is a rule that is generally ignored.

The Effects of Alcohol on Red Blood Cells in Relation to Bloodshot Eyes

A lesser known effect of alcohol on the circulatory system of the drinker is its ability to reduce the capacity of hemoglobin’s oxygen binding affinity, thereby affecting the ability for red blood cells to transport and carry oxygen to the cells of the individual and thereby reducing cellular function as well as general oxygen saturation of the blood.

This relates to the effect of bloodshot eyes after drinking by causing the red blood cells or RBCs to clump together, leading to an effect quite similar to vasodilation but quite different in terms of mechanism of action and subsequent health impact.

A reduced oxygen saturation and subsequent hemoglobin clumping within the circulatory system is only temporary, however, and is generally alleviated with the standard cures for a hangover – that is, rehydration with electrolyte rich fluids, eating macronutrient heavy food, as well as certain over the counter medications that aid in the symptomatic alleviation of the hangover.

Are Bloodshot Eyes After Drinking Permanent?

Generally, the conjunctivitis found in a drinker’s eyes during and after imbibing significant amounts of alcohol is temporary – though this is not quite the case in chronic alcoholism or individuals with certain medical conditions that are exacerbated by the drinking of alcoholic beverages.

Bright Future Recovery, an alcohol and drug detox center notes that chronic alcoholism may cause an individual to develop health problems relating to the appearance of bloodshot eyes and similar ocular-related issues such as cloudy vision and damage to the nerves behind the eyes – all of which can become quite complicated if left unchecked.

Generally, one or two drinks leading to bloodshot eyes the next morning is entirely treatable and usually alleviated in short order with a glass of water and some over the counter eye drops.

However, for more serious conditions with the same conjunctivitis-like symptoms, a variety of underlying problems relating to alcoholic consumption may be the cause.

Are Bloodshot Eyes After Drinking Unavoidable?

Considering the fact that bloodshot eyes after drinking is a multifaceted problem that requires a multitude of methods to prevent or treat, it is nonetheless possible to prevent or at least reduce the incidence and appearance of this particular hangover symptom.

This can be done through a variety of methods that are most effective when combined – the majority of which will also help treat any other symptoms encountered during the course of this hangover condition.


The first and most obvious of avenues to counter such post-drinking effects like bloodshot eyes and headaches is to hydrate properly, both during and after the session of drinking so as to provide the body adequate fluids to continue normal function while simultaneously excreting the exogenous ethanol.

However, hydration is not solely reserved for the intake of water, as proper hydration also requires that the individual replace any minerals and electrolytes lost during the body’s excretion of any alcohol that was absorbed, as well as the normal loss of electrolytes as is normal during day to day bodily function.

As such, sports drinks or even post-drinking specific electrolyte supplements can take care of this particular factor after a night of drinking.


Most over the counter eye drops that can be purchased at any grocery store or pharmacy can do wonders for the symptoms of alcohol consumption induced conjunctivitis, both due to the moisturizing and lubricating nature of the eyedrops as well as certain chemical compounds present in the mixture that act as vasoconstrictors.

Such over the counter medications present in eyedrops are that of tetrahydrozoline, a sympathomimetic amine vasoconstrictor and decongestant that immediately acts on the smaller venous bodies found in the eye so as to reduce the redness of the sclera and the raised appearance of said venous bodies.

Another common over the counter medication found in many eye drops is naphazoline, another type of vasoconstrictor and decongestant specifically used to relieve bloodshot and irritated eyes.

Apart from this, the majority of eyedrop brands found in most stores and pharmacies utilize synthetically derived lipid compounds that can mimic or replace lacrimal fluid so as to immediately relieve dry and raw eyes, a common symptom of drinking without sufficiently rehydrating.

NSAIDS (Non-steroidal anti-inflammatory drugs)

Somewhat less common a treatment for the bloodshot eyes found after a night of drinking and more likely used for the headache and nausea found thereafter, the use of non-steroidal anti-inflammatory drugs such as paracetamol and ibuprofen in the course of treating bloodshot eyes is only partially studied.

Nonetheless, certain studies have found that the use of low dose acetylsalicylic acid (Aspirin) can produce significant symptomatic relief in individuals with a condition known as ocular surface inflammatory disease – a condition quite similar to bloodshot and irritated eyes – via decreasing the osmolarity of lacrimal fluid.

It is important for the individual to first ascertain that their bloodshot eyes are due to the consumption of alcohol and not an underlying condition, however, as certain chronic diseases and injuries such as hyphema or thrombophlebitis may be exacerbated by the use of blood thinning drugs like NSAIDS. 

Cold Compress

Frequently employed in the course of first aid towards minor soft tissue injuries, the use of cold as a vasoconstricting agent is quite well studied throughout medical literature, and as such is not only a safe and efficient way of reducing the symptom of bloodshot eyes but also one that is sure to work.

cold or warm compress for eyes

To do so, purchasing an instant cold compress pack from a medical supply store or simply wrapping several ice cubes in a towel prior to pressing it against one’s eyes should be more than sufficient.

One must make sure that they understand that the vasoconstrictive effect of low temperatures is not instantaneous, however, as it may take up to half an hour before the redness and raised appearance of the eye’s veins shows signs of reduction.

Antihistamine Drugs (Anti-allergy drugs)

While the preferred treatment in terms of antihistamine drugs for bloodshot eyes is usually in the form of an eye drop suspension, using antihistamine tablets or capsules can also work – albeit at a slower pace and with a somewhat less focused effect.

A significant amount of antihistamine drugs are available over the counter or at a grocery store, with second generation antihistamine class medications like cetirizine and loratadine having a significantly reduced incidence of side effects present while still retaining the same irritation and congestion reducing mechanisms of action.

The patient must tread carefully when using oral antihistamine medications to reduce the presence of bloodshot eyes, however, as first generation antihistamines such as the commonly utilized Benadryl can not only make an individual more drowsy, but also worsen their dehydration by acting as an anticholinergic drug.

As such, it is best to utilize oral antihistamine drugs as a last resort or on days where one’s schedule is clear and the drowsiness imparted by certain types of antihistamine medications is not a hindrance or danger to the individual, especially in the case of driving.


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Dennis Clawson
I've worn glasses since 5th grade; I've come to terms with my poor vision and hope to share my experiences with others via Eyes FAQ. My goal is to share what I've learned and researched in hopes that it helps others with poor eye-sight.