{"id":15040,"date":"2024-08-13T10:30:19","date_gmt":"2024-08-13T14:30:19","guid":{"rendered":"https:\/\/www.veriheal.com\/blog\/?p=15040"},"modified":"2026-03-26T02:19:05","modified_gmt":"2026-03-26T06:19:05","slug":"the-science-behind-why-cannabis-can-cause-red-bloodshot-eyes","status":"publish","type":"post","link":"https:\/\/www.veriheal.com\/blog\/the-science-behind-why-cannabis-can-cause-red-bloodshot-eyes\/","title":{"rendered":"Why Does Weed Make Your Eyes Red?"},"content":{"rendered":"

One of the most common giveaways that one has consumed cannabis includes red, or bloodshot, eyes which could also feel dry and heavy-lidded. The association between red eyes and cannabis consumption is so well known that many prepare by having bought a bottle of over-the-counter eye drops. While the red, heavy-lidded eyes are said to pose no serious health risks, it’s still important to understand why our eyes go red and how to remedy the situation as necessary.\u00a0<\/span><\/p>\n

Science Explains Red Eyes\u00a0<\/b><\/h2>\n

Red eyes happen when the eye’s tiny blood vessels expand and that gives the eye a tinted pink or red appearance. Cannabis compounds have the ability to cause such changes in our bodies because they bind to the endocannabinoid receptors located all over the body. The connection between the receptors and cannabis as well as the full extent of effects of cannabis consumption are still busy being understood, however, the cause behind red eyes is getting more clarity.\u00a0<\/span><\/p>\n

McGill University’s Office for Science and Society explains<\/a> that<\/span> red eyes from smoking cannabis were previously attributed to irritation caused by the smoke itself but has since been found to be attributed to vasodilation. <\/span>Vasodilation is when the blood vessels are widened<\/span> as a result of relaxing the smooth muscle cells within the vessel walls. This widening of blood vessels leads to an increase in blood flow and a decrease in blood pressure.\u00a0<\/span><\/p>\n

The vasodilation caused by cannabis compounds relaxes the smooth muscle of the arteries and allows for more blood to flow through, which in turn causes the eyes to become red. The increase in blood flow is also said to be the cause behind dryness and the \u201cheavy\u201d feeling some have experienced. This effect, the increase of blood flow, is also why some cannabis consumers may feel dizzy.\u00a0<\/span>While this can be well tolerated by healthy individuals, those at risk of cardiovascular, or heart conditions<\/a> could inadvertently put themselves at risk by increasing their heart rate.\u00a0<\/span><\/p>\n

Tips to Avoid Red Eyes From Cannabis USe<\/b><\/h2>\n