The active ingredient in eye drops such as Visine is tetrahydrozoline HCI. Ingesting this substance can lead to a variety of harmful side effects such as dramatically lowering body temperature, causing severe breathing difficulty, respiratory failure, blurred vision, nausea, vomiting, blood pressure fluctuation, tremors, seizures and even coma. How long does it take for visine to make you sick?
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How much visine is lethal?