Charak Samhita
सिद्ध्यर्थं प्राक्प्रयुक्तस्य सिद्धस्याप्यौषधस्य तु । काठिन्यादूनभावाद्वा दोषोऽन्तः कुपितो महान् ॥३२९॥
Hence for the better results of the medicines administered, pathya (wholesome diet) must be followed even after the disease symptoms are completely disappeared.
english translation
siddhyarthaM prAkprayuktasya siddhasyApyauSadhasya tu । kAThinyAdUnabhAvAdvA doSo'ntaH kupito mahAn ॥329॥
hk transliteration by Sanscript