Which indirect moxa application is best for treating diarrhea and vomiting?

Using salt as an indirect moxa application for treating diarrhea and vomiting is effective due to its warming properties and ability to strengthen digestive function. Salt is known to have an astringent effect, which can help to stabilize the digestive system and reduce excess fluid, making it particularly useful in cases of diarrhea. Additionally, moxibustion with salt adds a thermal component, which can support the body's yang energy and offer relief from symptoms related to digestion.

In contrast, the other options may not align as closely with the goals of this treatment:

Aconite is primarily used for its warming ability, but it is more specific for treating severe cold conditions and is generally not associated with gastrointestinal issues.

Ginger, while beneficial for digestion and nausea, is not typically used in indirect moxibustion; it is usually consumed or applied in other forms for its warming and digestive properties.

Garlic has certain antibacterial and antiviral effects, but its application in this context is less direct for alleviating symptoms of diarrhea and vomiting. It can be stimulating to digestion but may not provide the needed warmth and astringency that salt offers.

Therefore, salt stands out as the most appropriate indirect moxa application for addressing these symptoms effectively.