Charak Samhita
तस्मात् पुरा शोधनमेव कार्यं बलानुरूपं न हि वृष्ययोगाः। सिध्यन्ति देहे मलिने प्रयुक्ताः क्लिष्टे यथा वाससि रागयोगाः ॥५१॥
Depending up on the strength of the person, purification should be done before he starts these aphrodisiac recipes, as a dirty cloth does not get properly colored, similarly in an uncleaned body, the aphrodisiac recipes do not produce the desired effects.
english translation
tasmAt purA zodhanameva kAryaM balAnurUpaM na hi vRSyayogAH। sidhyanti dehe maline prayuktAH kliSTe yathA vAsasi rAgayogAH ॥51॥
hk transliteration by Sanscript