Generally neutral foods will tonify Qi and blood and harmonize Yin and Yang. They can be used in combination with other types of foods to add vareity and choice or to decrease the harshness of a very cold or very hot diet.

Yin is qualities of inward, quiet, nighttime, maternal, cool and fluids. Yin tonics are foods which tonify the coolness and fluids of the body. Signs of Yang excess include seeking cool places, panting, thirst, red eyes, panting at night, dry skin, dry cough and restlessness.

Qi tonic foods are foods that warm the body allowing the body to develop and maintain warmth. Qi deficiency is seen as general weakness, fatigue, exercise intolerance, poor appetite, chronic diarrhea, loss of body weight, muscle atrophy, shortness of breath, asthma and/or urinary or fecal incontinence.

Yang is the opposite of yin. Yang qualities include outward, active, male, daytime, heat and inflammation. Yang tonic foods are the hottest or most heat generating foods. Yang deficiency animals are heat seeking, i.e. lie in front of fires or under bedcovers, have coldness to ears, nose, back and limbs.