Let us hear the ancient wisdom regarding disease and its understanding, as revealed in the sacred discourse. Disease is known by many names—evil, fever, affliction, disorder, corrupted ailment, consumption, suffering, and pain. Though the words differ, they all point to the same reality of bodily and mental distress. The sages have declared that the knowledge of diseases is fivefold: first, the cause; second, the prodromal signs or early indications; third, the manifest symptoms; fourth, the means of alleviation; and fifth, the progression or course of the disease. The cause of disease is described variously as the sign, reason, locus, condition, or origin. The prodrome is that which allows the wise to recognize the onset of illness before it fully arises. When a disease is about to emerge, but has not yet manifested due to a disturbance among the body’s humors, its signs are faint and subtle, varying according to the particular ailment. Once these signs become clear and unmistakable, they are called symptoms—also known as form, indication, sign, mark, or appearance. Relief from disease comes through the proper use of medicines, suitable foods, and a disciplined regimen. These measures counteract or reverse the cause and bring comfort to the afflicted. One should understand that what alleviates disease is called suitability, while that which aggravates it is termed unsuitability. The course of a disease is the process by which, through the corruption or spread of a disturbed humor, the disease develops and comes to fruition. This progression is distinguished by its number, variation, predominance, strength, timing, and other specifics, which the sages have explained, such as the eight types of fever. The variation and combination of the humors, the estimation of their relative portions, and whether one humor acts independently or depends on another, all reveal the predominance of a particular disease. The time of disease is determined by whether the causes and other contributing factors are fully or only partially present, by the strength or weakness of the illness, and by the time of day, night, or after eating. Thus, the meaning of cause has been explained, and Vyāsa himself will further instruct on this. But know this: the root cause of all diseases is the aggravation of the three humors—wind (vāta), bile (pitta), and phlegm (kapha). The various improper usages that provoke this aggravation have been described by the ancient teachers, including the threefold improper conjunctions of the three humors. Wind is aggravated by excessive consumption of bitter, pungent, astringent, or sour foods; by dryness, insufficient nourishment, running, excitement, staying awake at night, or speaking too loudly. Overexertion in action, fear, grief, anxiety, excessive exercise or sexual activity, and eating at the end of summer days and nights also disturb wind. Bile is provoked by pungent, salty, sharp, hot, and spicy foods; by anger and burning sensations; and during autumn, midday, and midnight. Phlegm is aggravated by foods that are sweet, sour, salty, unctuous, heavy, and cool; those that please the mouth and induce sleep, are hard to digest, and are eaten during the day or before sleep. Improper practices, such as forcing oneself to vomit after eating—especially when food is undigested, in the morning or early night—also give rise to disorders of phlegm. When all these factors are mixed together, there results a combined disorder of the humors. The same arises from eating incompatible, poorly digested, irregular, or mutually antagonistic foods. Consuming spoiled wine, water, dried vegetables, roots, oil-cakes, rotten meat, putrid, dried, or emaciated fish, and similar unwholesome foods disturbs the three humors. Further, disease may arise from corrupted bodily tissues, or from wind due to conflict, possession, or agitation. Other causes include corrupted food, excessive phlegm, afflictions at birth due to planetary influences, improper practices, indulgence in various sins, irregularities during childbirth for women, and improper treatments. When the humors, angered by these causes, follow the course of illness, one should swiftly resort to rejuvenation therapy, for the humors soon become disturbed and spread throughout the body. Now, Dhanvantari, the divine physician, speaks: “I shall explain the origin of fever, so that all fevers may be understood. Fever is the lord of diseases, the embodiment of sin, the king of death, the devourer, the ender. Fever arose from the wrath of Rudra when he destroyed Daksha’s sacrifice. This fever, full of burning and delusion, born of transgression, is fierce and known by many names. It manifests in various forms among all beings. In elephants, it is called Pākala; in horses, Abhitāpa; in donkeys, Alarka; in dogs, Kukrura. In clouds, it is Indramada; in water, Nīlikā; in luminous herbs, Jyoti; and in the earth, Ūṣara. The symptoms of fever arising from phlegm include nausea, vomiting, cough, stiffness, coldness, and eruptions on the skin and limbs. In each season, the onset and increase of these symptoms occur as appropriate; their alleviation is as stated in the causes, and the opposite measures bring relief. Other signs include loss of appetite, indigestion, stiffness, lethargy, burning in the heart, improper digestion, drowsiness, fatigue, distension, pain, and inactivity of the humors. Excessive salivation, nausea, loss of hunger, tastelessness in the mouth, clarity, heat, heaviness of the limbs, and frequent urination are not the signs of properly digested food or general malaise, but are symptoms of undigested fever. When digestion is complete, fever is marked by hunger, dryness, lightness of the limbs, and tenderness. The activity of the humors after eight days is also a sign of this state. Fever may arise by its own symptoms or by contagion. When it arises from contact, it presents with headache, fainting, vomiting, burning of the body, dryness of throat and mouth, loss of taste, pain in the joints, insomnia, confusion, horripilation, yawning, and excessive speech—these result from wind and bile. Fever caused by phlegm and wind is marked by loss of heat, loss of appetite, pain in the joints and head, spitting, labored breathing, cough, pallor, coldness, stiffness, darkness before the eyes, dizziness, and drowsiness. When fever arises from phlegm and bile, it is characterized by coldness, stiffness, sweating, burning, instability, thirst, cough, the activity of phlegm and bile, confusion, drowsiness, and a coated and bitter mouth. The one who knows all these signs experiences repeated burning; then comes intense sleep, wakefulness during the day, and sleeplessness at night. There may be constant sleep or none at all; profuse sweating may occur, or not; natural activities such as singing, dancing, and laughter cease. The eyes become tearful, impure, red, sunken, with trembling lashes; there is pain at the sides of the eyeballs, in the head, joints, and bones, and dizziness. The ears ring and ache, or feel extremely cold, or not; the tongue is burnt, rough, heavy, and the joints of the limbs are weak and trembling. There may be spitting of blood and bile, rolling of the head, intense thirst, and the appearance of dark or red patches and circles on the body. Pain in the heart, frequent excretion of waste, scanty or excessive discharges, an oily mouth, loss of strength, hoarseness of voice, and delirious speech may also be present. Thus, the sages have described the nature, causes, and signs of disease and fever, so that the wise may recognize, prevent, and treat them with discernment and care.