Botulinum toxin is one of the most poisonous substances known to man. Scientists have estimated that a single gram could kill as many as 1 million people and a couple of kilograms could kill every human on earth. In high concentrations, botulinum toxin can result in botulism, a severe, life-threatening illness. Botulism, left untreated, may result in respiratory failure and death. Despite botulinum toxin being so toxic, Botox is in huge demand.
Spread of toxin effects. The effect of botulinum toxin may affect areas away from the injection site and cause serious symptoms including: loss of strength and all-over muscle weakness, double vision, blurred vision and drooping eyelids, hoarseness or change or loss of voice, trouble saying words clearly, loss of bladder control, trouble breathing, and trouble swallowing.