In the novel The Mirror Crack'd from Side to Side, Calmo (Hyethyldexylbarboquindelorytate “or some such name”) is the trade name of a tranquillising drug which in prescribed fairly freely available in the US. It was also a staple item in the Marina Gregg household. According to Dr Gilchrist, Marina Gregg "Lives on it, pretty well" said Dr Gilchrist. Ella Zielinsky takes it and so does Hailey Preston. Dr Gilchrist tells Inspector Craddock that the durg "calms you or it peps you up, makes you feel you could do things which otherwise you might fancy that you couldn't." It is not normally considered dangerous if taken at the proper dosage but Heather Badcock had apparently ingested 6 times the normal dose.