Charak Samhita
नाल्पं हन्त्यौषधं व्याधिं यथाऽऽपोऽल्पा महानलम् । दोषवच्चातिमात्रं स्यात्सस्यस्यात्युदकं यथा ॥३१३॥
[Importance of proper dosage] As very small quantity of water cannot extinguish big fire, similarly small doses (insufficient dose) of medicine cannot inhibit or treat disease.
english translation
nAlpaM hantyauSadhaM vyAdhiM yathA''po'lpA mahAnalam । doSavaccAtimAtraM syAtsasyasyAtyudakaM yathA ॥313॥
hk transliteration by Sanscript