Johnson & Johnson, which now produce Visine since acquiring Pfizer, warns that ingesting of Visine can induce dangerous side effects due to the odorless and tasteless toxic ingredient, tetrahydrozoline hydrochloride such as:

• Dangerously low body temperature (hypothermia)
• Blurred vision
• Nausea and vomiting
• Difficulty in breathing or even a complete halt in breathing
• Elevating (hypertension) then dropping (hypotension) blood pressure
• Possible coma
•  Seizures and tremors

Pfizer recommends that you seek immediate medical attention or contact a poison control center if you have ingested Visine. Tetrahydrozoline hydrochloride is a vasoconstricting agent, which should not have GI side effects but can affect central nervous system and blood vessel, RevolutionHealth.com reports.