The herbal reference, done carefully.

Garlic (Allium sativum) is a bulbous perennial in the onion family, recognized for its sharp flavor and characteristic odor. It is widely used in cooking, and crushed fresh garlic contains allicin. NCCIH says garlic supplements may lower cholesterol, blood pressure and blood sugar to a small extent, but very little research has tested claims that they boost immunity.

Ginger (Zingiber officinale) is a perennial plant reaching about 2 ft (60 cm), with lance-shaped leaves and white or yellowish flower spikes. Its rhizome (underground stem) is pungent, aromatic, and widely used as a culinary spice. NCCIH says ginger may help nausea and vomiting in pregnancy and might reduce menstrual cramps, but most studies of motion sickness have not found it helpful.

Lavender (Lavandula officinalis, also known as L. angustifolia) is a small, perennial shrub that can grow about 3 ft (1 m) high, characterized by its narrow, silver-green leaves and spiked violet-blue flowers. Renowned for its sweet aroma, lavender has a long history in traditional medicine for improving mood and sleep, and NCCIH says it is promoted today for calming anxiety and stress. NCCIH says studies suggest an oral lavender oil product might help anxiety, but more high-quality research is needed to reach reliable conclusions.

Turmeric (Curcuma longa) is a perennial with a thick rhizome, growing to about 3 ft (90 cm), featuring lance-shaped leaves and pale yellow flowers. Renowned for its bright yellow-orange color, turmeric is a spice commonly employed in Indian cooking and in Ayurveda, where it has been used for indigestion, colds, skin infections, and arthritis. NCCIH says there isn't enough evidence to conclude that turmeric or curcumin is beneficial for any health purpose.

Hawthorn (Crataegus spp.) is a deciduous, thorny tree reaching up to about 26 ft (8 m), adorned with small lobed leaves, clusters of white blossoms, and bright red berries. Hawthorn has a long history in European medicine as a heart tonic and was traditionally used for heart disease, digestion and blood circulation. NCCIH says there is little or no quality evidence on hawthorn for most conditions, and conflicting evidence in heart failure.

Echinacea (especially E. angustifolia and E. purpurea) is a perennial promoted today for colds on the idea that it may stimulate the immune system; NCCIH says taking echinacea may slightly reduce the chance of catching a cold, but it is still unclear whether it shortens a cold. Native Americans used echinacea for respiratory tract infections, tooth pain and snakebite; NCCIH says it is unclear whether echinacea helps other health conditions, including eczema.

Valerian (Valeriana officinalis) is an upright, clump-forming perennial reaching about 4 ft (1.2 m), with divided, pinnate leaves and pinkish-white clusters of small flowers. Known for its pungent (often unpleasant) smell, valerian has been used medicinally since early Greece and Rome, historically for insomnia, migraine, fatigue and stomach cramps. NCCIH says the evidence on sleep is inconsistent and there is not enough evidence to know whether valerian helps any health condition.

Peppermint (Mentha × piperita) is a fast-growing, square-stemmed herb (commonly about 32 in / 80 cm tall), with lanceolate, serrated leaves and purplish flowers. A natural hybrid of watermint and spearmint, peppermint is renowned for its cooling, aromatic flavor, and mint plants have been used for digestive disorders since ancient Greece, Rome and Egypt. NCCIH says a small amount of research suggests enteric-coated peppermint oil capsules may improve IBS symptoms in adults, but there is not enough evidence to know whether peppermint leaf helps any condition.