The symptoms of hyoscyamine toxicity, also known as anticholinergic syndrome, can be severe and include dry mouth, blurred vision, photophobia, tachycardia, urinary retention, and hyperthermia. In severe cases, it can lead to hallucinations, seizures, and coma. The phrase "blind as a bat, dry as a bone, red as a beet, mad as a hatter, hot as a hare" is often used to describe the symptoms of severe anticholinergic toxicity.
