NationsHealth ( NHRX) said Robert Gregg ceased to serve as chief operating officer last Wednesday. Gregg will continue to serve "in other capacities," the Sunrise, Fla., home health care service provider said, adding that it hoped to find a replacement by year-end. "We want to thank Robert for his valuable contribution to the Company's development and growth since its inception," said CEO Glenn Parker. "His entrepreneurial vision has been a leading factor in our success to date." On Wednesday, NationsHealth shares fell 12 cents to $7.88.