Atropa belladonna (deadly nightshade) is a relatively rare plant and severe poisoning is not common. The berries, which are black, ripen from August to October and are the most commonly ingested part of the plant. However, all parts of the plant are toxic. The berries contain atropine and other unidentified alkaloids, the leaves hyoscine and atropine, and the roots hyoscine. All these alkaloids have an anticholinergic effect which may cause a dry mouth, dilated pupils with blurred vision, tachycardia, hallucinations and pyrexia. There may also be ataxia, agitation, disorientation and confusion. In severe cases there may be convulsions, coma, respiratory depression and arrhythmias. Clinical effects may be delayed in onset for up to 12 hours, and prolonged for several days.