Grapefruit seed extract is a popular "natural antimicrobial" often touted for it's ability to fight infections. However, numerous studies appear to indicate that the antimicrobial effects are due to chemical contaminants.
Vitamin D has long been known to play a role in bone health. More recently, evidence is starting to show that it may be a significant factor in the treatment of mental health.
Pulsed-electromagnetic field therapy or PEMF appears to show promise for treating a number of different conditions, including pain. However, it is difficult to draw firm conclusions as the different devices and treatment parameters make PEMF difficult to study.
Elderberry has a long history of medicinal use, including for the treatment of colds and flu. Most of the latest clinical research appears to support the benefits of elderberry in reducing the durations and severity of illness.