Depending on the type of medicine and its chemical components, one of the following two methods can be used to dry plant-based medicines: The two mains drying techniques are (a) drying in the sun outside and (b) drying in a heated environment indoors. Depending on the material to be dried, open air natural heat drying may be carried out in the sun or the shade. A thermal process called drying employs heat to remove liquid from a solid-liquid mixture and to speed up evaporation through a vacuum. In order to do this, the liquid is transferred from a surface into an unsaturated vapour phase. Many drying technologies are available to accomplish these goals, however the choices are very limited.