The mantra for protection from disease in Hinduism is dedicated to Dhanwantari. The mantra should be chanted early in the morning just at sunrise. Here is the mantra for protection from disease.
नमो भगवते महासुदर्शनाय वासुदेवाय
धन्वंतरायेर्
अमृतकलश हस्ताय सर्व भयविनाशाय सर्व रोगनिवारणाय
त्रिलोकपथाय त्रिलोकनाथाय श्री महाविष्णुस्वरूप
Namo Bhagavate Mahasudarshanaya Vasudevaya Dhanvatarayer
Amrutakalasha Hastaya Sarva Bhyavinashaya Sarva Roganivaranaya
Trailokapadaya Trilokanadaya Sri Mahavishnuswarupaye
अमृतकलश हस्ताय सर्व भयविनाशाय सर्व रोगनिवारणाय
त्रिलोकपथाय त्रिलोकनाथाय श्री महाविष्णुस्वरूप
Namo Bhagavate Mahasudarshanaya Vasudevaya Dhanvatarayer
Amrutakalasha Hastaya Sarva Bhyavinashaya Sarva Roganivaranaya
Trailokapadaya Trilokanadaya Sri Mahavishnuswarupaye
The mantra should be chanted 21 times in the morning.
After chanting the mantra the person should squeeze a lemon into lukewarm water and drink it.