Charak Samhita
एको हेतुरनेकस्य तथैकस्यैक एव हि । व्याधेरेकस्य चानेको बहूनां बहवोऽपि च ॥२४॥
॥ Diagnostic aspect of etiological factors॥ One causative factor may cause one or many diseases. Many causative factors may result in a single disease or may cause several diseases.
english translation
eko heturanekasya tathaikasyaika eva hi । vyAdherekasya cAneko bahUnAM bahavo'pi ca ॥24॥
hk transliteration by Sanscript