Umm Asim (may Allah have mercy on her), the wife of Sayyiduna Utbah bin Farqad (may Allah be pleased with him), narrated: We, several wives, were with Utbah, and each of us wanted to be more fragrant than her companion; yet Utbah was the most fragrant, and when he went out he was recognised by his fragrance. I asked her (the wife) the reason for it, and she said: He was afflicted with a rash in the time of the Messenger of Allah (peace and blessings be upon him). He complained of it to him (peace and blessings be upon him), and he (peace and blessings be upon him) gave him an order; he sat in front of him (peace and blessings be upon him) and placed his hand over his private parts. Then the Prophet (peace and blessings be upon him) spat into his hand and passed it over his back and belly.
Hadith Referenceالمعجم الكبير للطبراني / باب العين / 14402