Medicinal/məˈdɪsɪnl/ Definition 1 of 2Pro Tip 1/3Historical Use Understand how ancient cultures used medicinal substances for healing. Ancient texts describe the medicinal powers of plants like aloe. Pro Tip 2/3Not Always Safe Remember that 'medicinal' doesn't guarantee safety; some can be harmful if misused. The medicinal herb can be toxic in high doses. Pro Tip 3/3Natural Sources Identify that 'medicinal' often refers to natural sources, not just pharmaceuticals. Local tribes used the tree bark for its medicinal qualities.