Waltheria ovata is primarily used in traditional medicine systems, particularly in parts of Africa and South America, for the treatment of skin conditions such as rashes and hives. Ethnobotanical surveys and reports indicate that leaves and stems of Waltheria ovata are applied topically, often as poultices or decoctions, to soothe inflamed skin and reduce itching. The traditional use is based on empirical knowledge passed down through generations, with healers and local populations employing the plant for its perceived anti-inflammatory and soothing properties.

Scientifically, there is limited direct evidence supporting the efficacy of Waltheria ovata specifically for rashes or hives. Some phytochemical studies have identified the presence of flavonoids, alkaloids, and other secondary metabolites with potential anti-inflammatory and antimicrobial effects, but these findings are mostly preliminary and not directly linked to clinical outcomes in humans with skin conditions. There are no robust clinical trials or pharmacological studies that specifically evaluate its effects on rashes or urticaria (hives).

In summary, the use of Waltheria ovata for rashes and hives is justified primarily by traditional practice rather than validated scientific research. While some of its constituents may have properties relevant to skin health, the current evidence base does not strongly support its clinical effectiveness, and more research would be needed to establish its safety and efficacy for these uses.