Barium chloride, along with other water-soluble barium salts, is highly toxic. It irritates eyes and skin, causing redness and pain. It damages kidneys. Fatal dose of barium chloride for a human has been reported to be about 0.8-0.9 g. Systemic effects of acute barium chloride toxicity include abdominal pain, diarrhea, nausea, vomiting, cardiac arrhythmia, muscular paralysis, and death. The  ions compete with the  ions, causing the muscle fibers to be electrically unexcitable, thus causing weakness and paralysis of the body. Sodium sulfate and magnesium sulfate are potential antidotes because they form barium sulfate BaSO, which is relatively non-toxic because of its insolubility in water.
Barium chloride is not classified as a human carcinogen.