A summary of Southern California-related business litigation developments during the past week.

Suits Against Japanese Firm Allege Poisoning: Dual lawsuits were filed in state and federal court against Showa Denko K.K. of Japan on behalf of roughly 120 people who allege that they or members of their family were poisoned by L-tryptophan, an amino acid that was banned in the United States last April. The multimillion-dollar lawsuits assert that Showa Denko manufactured L-tryptophan and put the amino acid through a purification process “without testing, research or knowledge as to what the effect would be in the human body.” The suits assert that Showa Denko “knew the product was the cause of various medical conditions” resulting in injury. (Case Nos. 004685 and 90-6018, Filed Nov. 8, 1990)