Atropine is an M-cholinergic receptor blocker, which can release smooth muscle spasm, including release vasospasm, improve microvascular circulation, inhibit glandular secretion, release vagus nerve for heart inhibition, make heart beat faster, dilate pupil, make eye pressure rise, and excite respiratory center. Clinically used for rescuing infectious toxic shock, treating antimony-induced As syndrome, treating organophosphorus pesticide poisoning, relieving visceral colic, can be used for preanesthetic administration, for ophthalmic pupil dilation, regulating functional paralysis. It is used for keratitis and iridocyclitis. The drug is prescribed and must be administered under medical supervision. Common adverse reactions include constipation, decreased sweating, dryness of the mouth, nose and throat, blurred vision, flushing of the skin, difficulty urinating, and dry mouth especially in elderly patients, especially in men. Rare adverse reactions include increased eye pressure, allergic rash or herpes. Overdose manifests as clumsy and unsteady movements, confusion, convulsions, hallucinations, delirium, mostly in elderly patients. Shortness of breath with difficulty, slurred speech, abnormally fast heartbeat, agitation, nervousness, fidgeting, mostly seen in children, etc. Very high doses may cause convulsions, excitement, and blurred vision. There is a risk of cardiac arrest with intravenous administration, and in some patients, tachycardia or ventricular fibrillation may occur. This complication may be due to dosages above 1 mg, but sometimes dosages of 0.5 mg can also cause these complications. The most common allergic reactions are contact dermatitis and conjunctivitis. The use of atropine eye drops sometimes causes irritant conjunctivitis when used with pressure on the tear sac, especially in children. Absorption via the nasolacrimal duct can produce systemic symptoms, mainly manifested as dry mouth, decreased salivation, absence of sweating, skin flushing, dizziness, increased heart rate, especially in the face, neck and upper trunk may be followed by desquamation.