Is it useful to apply vinegar to treat sprained feet?

Five times the seeds with vinegar external application does not treat foot sprains.
Five times the nature of sour, astringent, cold, to the lungs, large intestine, kidney meridian, with astringent lung (astringent lung qi) to lower the fire, astringent intestines to stop diarrhea (through the enhancement of intestinal astringency to alleviate diarrhea), astringent sweating, stopping bleeding, and collect dampness and astringent sores (to reduce the invasion of dampness to promote the healing of the sores) efficacy. It can be decocted and taken internally or applied externally.
Five times the seeds of external use in the clinic is commonly used in the treatment of bleeding hemorrhoids, traumatic bleeding, carbuncles, swollen sores (skin local redness, swelling, heat, pain, etc.) and wet skin, etc., the nature of its bias in the astringent hemostasis (astringent effect of the drug to treat bleeding conditions), and bruises need to be activated to remove blood stasis, so the five times the seeds of the foot can not be used to treat foot sprains.
Internal five times the seeds are often used in the treatment of lung deficiency cough, lung heat cough phlegm, diarrhea for a long time, spontaneous sweating (involuntary sweating during the day, sweating is aggravated by the slightest movement), night sweating (sweating abnormally after going to sleep, waking up sweating stops), and blood in the stools, and so on. It should not be used by those who have wind-cold, solid heat in the lungs, or damp-heat diarrhea (diarrhea caused by feeling damp-heat evil).
It is recommended that patients in need of timely medical treatment, under the guidance of the doctor’s diagnosis and treatment with medication.