Four persons were arrested by Fairfax City police yesterday and charged with practicing medicine without a license at the Let's Live Center, which has had an office at 4025 Williamsburg Square in Fairfax City for more than two years, according to Fairfax City spokesman Thomas Welle.

They were practicing iridology, which involves studying a person's eyes, especially the iris, to determine what is wrong with them, Welle said. The treatment prescribed usually involved vitamins and an enema, administered by a colon therapist, he said.

An undercover state health officer visited the center at least four times this summer after an area resident filed a complaint with the state health department in June, Welle said.

He said a brochure for the center describes it as a division of Palma Christi Inc., a multidiscipline health care facility.

A woman reached at the Let's Live Center yesterday said she could not comment on the arrests and that the center is hiring a lawyer.

The arrests were made by Fairfax City police during the woman undercover agent's appointment yesterday,Welle said. The agent, who does not have arrest powers, was not identified. Welle said she was charged $35 a visit.

Conviction of practicing medicine without a license, a misdemeanor, carries a maximum penalty of one year in jail and a $1,000 fine.

The four who were arrested, all released on unsecured $1,000 bonds, were identified as Karen Kay Yenckell, 38, S. William Moore, 32, and his wife D. Marie Moore, all living in the town house-office address, and Janine C. Assa, 20, of 4326 Duncan Dr., Annandale, identified as a colon therapist.