Hi there, great question. First let's talk about why your eyes go red when smoking cannabis.

Cannabis affects the body in many ways. One effect is that it acts as a vasodilator, that is, it makes the blood vessels bigger (dilated). This leads to changes in the body such as lower blood pressure, which the body tries to counteract by making the heart beat faster to get pressure back to normal. In your eyes the enlarged blood vessels are more visible against the whites of the eye and cause the blood-shot look. As the cannabis wears off so does its vasodilating effect and the eyes return to normal.

Not everyone's eyes go red every time; the effect varies between people. Some people report also having very dry itchy eyes or glassy eyes. Red eyes are just one effect of being stoned.

How do you know you're stoned? It varies from individual to individual in both the experiences and intensity. Cannabis enters the bloodstream very quickly when it's smoked so its effect is immediate. However, many things including how often or how much you use (tolerance), the strength of the cannabis, and also how you are feeling at the time (e.g. depressed, anxious) can affect the impact of cannabis on your mind and body.

Most people report a change in perceptions (sounds, smells, visions, time, etc.) such that their experiences of events such as music are heightened, and it's this sensation that many users like about taking cannabis. The downside is that it can also alter your grasp of what people are saying or doing and lead to misunderstandings.

Cannabis affects the body and can being stoned can induce relaxation but it can reduce reaction times so conversation and activity is reduced. That's one reason why driving or using machinery is dangerous when stoned. Cannabis also increases appetite and hunger (the munchies), feelings of thirst, and heart rate. When combined with alcohol cannabis can lead to "spinning out" where the user feels dizzy and faint and colour drains from their face and they can even feel nauseous.

Many users report changes in their motivation and thinking and report feeling lazy and forgetful. Frequently, cannabis users say they feel anxious and paranoid, which usually goes away as the cannabis effect does. However for some people this feeling will continue when they aren't stoned and they will need to look at changing their use and might need to talk to a professional about their mental health. Hope this answers your questions.