Atropine is a medication derived from the belladonna plant, also known as deadly nightshade. It belongs to a class of drugs called anticholinergics, which work by blocking the action of a neurotransmitter called acetylcholine. Atropine is commonly used to treat bradycardia (slow heart rate), to reduce saliva production during surgery, and as an antidote for certain types of poisoning. In addition to its medical uses, atropine can also cause pupil dilation, which is why it is sometimes used in eye examinations. While generally safe when used appropriately, atropine can have side effects, including dry mouth, blurred vision, and increased heart rate.