What is the ruling on smoking natural, non-intoxicating herbs, such as lavender, for medicinal benefits?

The basic principle is that everything harmful to a human being is forbidden, based on the Almighty’s saying: ﴿And do not kill yourselves﴾ and His saying: ﴿And do not cast yourselves with your own hands into destruction﴾, and based on the Prophet’s (peace be upon him) saying: “There should be neither harm nor reciprocating harm.” So, if inhaling the smoke of herbs is harmful, it is forbidden. But if it is medically beneficial, then there is no harm in it, as the basic principle is permissibility. Specialists should be consulted to determine the intended benefit and whether it is achieved with combustion or not.