A native of Wake Forest, North Carolina, Rachel Harris Larson was the oldest daughter and had 4 siblings.

[3] Larson's studies at the NIDR on the interrelationships of genetics, nutrition, and bacteriology in dental caries in experimental animals brought her international recognition.

She was a fellow of the American College of Dentists and presented a DHEW superior service honor award.

She remarried in 1971 to John W. Henry but continued to use the surname Larson to retain her established identity in the scientific community and literature.

After retirement, she did volunteer work in the Washington area and spent time with husband at their mountain cottage near Front Royal, Virginia.