Also called flint, silica is used by homeopaths to treat symptoms of chronic diseases where there is general weakness, sweating, and sensitivity to cold and a lack of either physical or emotional strength. It is a much-prescribed homeopathic medicine to treat conditions associated with frequent and recurrent illnesses that occur because of a weakened immune system. These include frequent colds, flu, and chronic ear infections especially those with a thick, yellow discharge or fluid in the middle ear.

Silica is also useful in throwing out material from the body. It is used to remove splinters, bits of embedded glass, and other foreign irritants. It also aids in the elimination of stools from the rectum. Certain skin and bone complaints can also be treated with silica. These include fractures that are slow to heal, rough or peeling lips, acne, weak nails, and ingrown toenails. Other ailments for which silica is considered an appropriate homeopathic remedy are migraines that begin in the back of the head and extend to the eyes, heavy sweating around the head and neck, mumps, dental abscesses, vaginal cysts, mastitis in breast-feeding women, and general low stamina.

One diagnostic tool in homeopathy is to observe when symptoms improve or worsen as a clue to which remedy to use. Homeopathy also ascribes certain personality types to certain remedies. The silica personality is said to be chronically exhausted and lacking in stamina. These people are happy to sit without taking any action. The silica personality always feels cold intensely. These people are often intellectually bright but lack of confidence.