Ellen G. White, Counsels On Health, p. 90:
Pure air, sunlight, abstemiousness, rest, exercise, proper diet, the use of water, trust in divine power-these are the true remedies. Every person should have a knowledge of nature’s remedial agencies and how to apply them. It is essential both to understand the principles involved in the treatment of the sick and to have a practical training that will enable one rightly to use this knowledge.
The use of natural remedies requires an amount of care and effort that many are not willing to give. Nature’s process of healing and upbuilding is gradual, and to the impatient it seems slow. The surrender of hurtful indulgences requires sacrifice. But in the end it will be found that nature, untrammeled, does her work wisely and well. Those who persevere in obedience to her laws will reap the reward in health of body and health of mind.