In February 1928, Howse was reappointed Minister for Health and also made Minister for Home and Territories. He relinquished the latter portfolio in November 1928 after that year's election. Howse made a significant impact during his two periods as health minister. He helped establish the Federal Health Council of Australia, supported the formation of the Australian College of Surgeons and the first conference of Australian cancer organisations, and was instrumental in the decision to site the Australian Institute of Anatomy in Canberra. In 1928, he convinced cabinet to spend the considerable sum of £100,000 to establish one of the world's first radium banks, allowing Australia to become a centre of radiological research. He was also credited with inspiring public confidence in Commonwealth Serum Laboratories and the government's immunisation programs, at a time when a series of fatalities had led to a distrust of immunisation among the general population.