a physician made mention of the use of frogs in a remedy in the presence of the Messenger of Allah and the Messengher of Allah forbade killing them. (sahih) (Using translation from Nasāʾī 4355)  

أَنَّ طَبِيبًا ذَكَرَ ضِفْدَعًا فِي دَوَاءٍ عِنْدَ رَسُولِ اللهِ ﷺ «فَنَهَى رَسُولُ اللهِ ﷺ عَنْ قَتْلِهِ»