Chloroform was used as an anaesthetic during childbirth and surgery, from about 1847. It replaced ether which was used before. Chloroform is very poisonous, and can cause breathing problems, and problems with the heart. Death from chloroform can come from cardiac arrest. When Chloroform is stored for a longer time period, it can decay into Phosgene. Phosgene was a chemical weapon (poison gas) used during the First World War. Chloroform can cause birth defects and lead to miscarriages. It may cause cancer.