The effects of sarin are many in number. Because sarin attacks acetylcholinesterase in both muscarinic and nicotinic junctions, it is easiest to divide the list of symptoms this way:
| Muscarinic Effects | Nicotinic Effects |
| Eye pain, darkness of visual field, miosis (constriction of pupil, sometimes smaller than 1mm), loss of dark adaptation, nausea, vomiting, stomach cramping, fecal incontinence, rhinorrhea (runny nose), wheezing, coughing, chest tightness, dyspnea (difficulty breathing), hypotension (low blood pressure), and bradycardia (slow heart beat). | Twitching, cramping, weakness, paralysis, fasciculations (muscle twitching), hyperglycemia, ketosis (build up of ketone in blood), leukocytosis, and tachycardia (fast heartbeat). |
Other general effects include anxiety, restlessness, insomnia, depression, confusion, ataxia, convulsions, coma, and tremors. Some signs of toxicity are short term and manifest quickly. Other effects may be long term. In the incidents that took place in Tokyo, some of the effects were present a year after the incident. In a few of the more severe cases of sarin poisoning, effects were still present 2 years after the initial exposure.