The manchineel tree is deadly

All parts of the tree contain strong toxins. Its milky white sap contains phorbol and other skin irritants, producing strong allergic contact dermatitis. Standing beneath the tree during rain will cause blistering of the skin from mere contact with this liquid: even a small drop of rain with the milky substance in it will cause the skin to blister. The sap has also been known to damage the paint on cars. Burning the tree may cause ocular injuries if the smoke reaches the eyes. Contact with its milky sap (latex) produces bullous dermatitis, acute keratoconjunctivitis and possibly large corneal epithelial defects. 

Although the fruit is potentially fatal if eaten, no such occurrences have been reported in the modern literature. Ingestion can produce severe gastroenteritis with bleeding, shock, and bacterial superinfection, as well as the potential for airway compromise due to edema. When ingested, the fruit is reportedly "pleasantly sweet" at first, with a subsequent "strange peppery feeling ... gradually progress[ing] to a burning, tearing sensation and tightness of the throat." Symptoms continue to worsen until the patient can "barely swallow solid food because of the excruciating pain and the feeling of a huge obstructing pharyngeal lump.”