Botulism can cause a variety of symptoms, including weakness, double or blurred vision, drooping eyelids, difficulty swallowing, slurred speech, shortness of breath, vomiting, belly pain, diarrhea, and later, severe constipation and difficulty urinating. Infants with botulism may appear lethargic, have poor muscle tone, poor feeding, drooling, and a weak cry. Prompt diagnosis and treatment are crucial, as the symptoms can be severe and potentially life-threatening.