Background: Doctor–patient sexual relationship is considered to be unfair because the first party would be abusing the second party’s vulnerability. The prohibition of this relationship is noted in the Hippocratic oath. Currently, a reprise of the use of oaths in medical schools can be observed.Aim: To determine whether the prohibition has been maintained and how its expression has varied in the oaths during different periods.Methods: 50 oaths were studied: 13 ancient–medieval and 37 modern–contemporary. Of the 50 texts, 19 were versions (...) of the original oaths. The oaths that pointed out the prohibited doctor–patient relationship referred to any sexual aspect or included paragraphs that began as the Hippocratic oath does were noted.Results: Of the 24 texts that expressed the prohibition, 8 were ancient–medieval and 16 were modern–contemporary. Some expressly call it Hippocratic oath, many use general terminology and others describe it in association with other commitments .Conclusions: The clause on the prohibition of the doctor–patient sexual relationship in Hippocratic oath was included to be for legal, economic and social reasons at the time. That the clause is found mostly in the ancient–medieval oaths can be attributed to the influence of the original. This commitment is generalised and associated with others by contemporary formulas. Currently, sexual relationships are the subject of legal and ethical analysis and their inclusion in the oaths is being debated. (shrink)