Divided into completely parasitic or semi-parasitic, annual or perennial herbs. They will grow in the roots of the host. All parasites will be completely parasitic on the host, and photosynthesis cannot be carried out without chlorophyll. Semi-parasitic species (transformed from Labiatae) can carry out photosynthesis and parasitize on the host. Except the semi-parasitic species is green, others are yellow, brown, purple or white, but there are few kinds of green.

Under this family, most species only grow swollen short roots or swollen organ roots, simple or comprehensive roots, and only a few species have huge roots. Moreover, they will be connected to the root of the host with hook-shaped haustorium to absorb the nutrients of the host, so they are a plant family that will harm crops.