Racisin is a type of toxic protein found in the seeds of the castor oil plant (Ricinus communis). It is known for its potency and can cause severe health issues if ingested, inhaled, or injected, leading to symptoms like vomiting, diarrhea, and organ failure. Due to its toxicity, racisin is classified as a bioterrorism agent and is highly regulated in many countries. Its use in research is strictly controlled due to its dangerous nature.