Glossary of Materia Medica of the Bhāvaprakāśa 13.61

13.61

viṣavadvanavṛkṣāṇāṃ patrādyairdūṣitaṃ yataḥ
audbhidaṃ vā'ntarikṣaṃ vā kaupaṃ vā prāvṛṣi smṛtam
śastaṃ śaradi nādeyaṃ nīramaṃśūdakaṃ param

because it is contaminated by poisonous leaves and other parts of forest trees. / Spring-emergent, rainwater, or well water is prescribed during the rainy season; / in autumn, river water is recommended, and aṃśūdaka is foremost.