Astanga Hrudaya
वर्षादिषु तु पित्तस्य, श्लेष्मणः शिशिरादिषु। चीयते लघुरूक्षाभिरोषधीभिः समीरणः॥२५॥
Vata undergoes chaya (mild increase) during summer by the use of Plants possessing such as lightness, dryness etc. It is especially so, in the bodies of persons possessing such qualities.
english translation