Pepper – Black essential oil is used in aromatherapy as a carminative and antispasmodic to help relieve digestive disorders or constipation, as well as to relieve symptoms of joint and muscle pain associated with sprains, strains, arthritis and rheumatoid arthritis. Piper nigrum Topical (Adults): Mix 1 to 2 drops in 1/2 teaspoon (2.5ml) of vegetable oil; apply to the affected area 3 times a day.