He is an expert in pharmacognosy, and has a deep knowledge about the medicinal value of plants.

He is a specialist in that field.

This medicinal shampoo helps maintain scalp health.

He is majoring in botany at university.

This herbal medicine helps to alleviate the symptoms of a cold.

My grandmother always believes in natural remedies and chooses natural treatments.

I'm always amazed by his extensive knowledge.

Your opinion has great value.

His specialty is physics.

He was holding my hand tightly.