While an undergraduate, McCowen was offered the position of assistant physician on the staff of the State Hospital for the Insane in Mt.

In 1894, she became president of the medical board of the Iowa State Nursery of the Children's Home Society, located in Davenport.

At the World's Congress on Geology, she read a paper on “Crinoids,” illustrated with specimens from the Davenport Academy of Sciences, which address attracted much attention and a copy of it was requested by the British Museum, London, and Johns Hopkins University, Baltimore, Maryland.

At the congresses in the Woman's Building, in October, she spoke upon “The Child Problem of To-day.” McCowen was also a member of the jury of awards of the World's Columbian Exposition, in the department of medical and surgical appliances, artificial limbs, sanitary exhibits, and others.

[4] McCowen was a Scott County, Iowa Medical Society member, serving as its secretary from 1880 to 1882, president from 1883 to 1884, and treasurer beginning in 1885.

She became the third woman to be elected a member of the Medico-Legal Society of New York in 1885, and became vice president of the society in 1888; was a vice president of the International Congress of Medical Jurisprudence, New York, 1889; represented the state of Iowa at the annual meetings of the National Conference of Charities and Correction since 1882, and was secretary for Iowa, 1882–92; was a member of the Davenport Academy of Natural Sciences, twice president, 1889–90,[5] and a member of its publication committee beginning in 1890; of the American Association for the Advancement of Science; of the National Science Club; and of the American Association for the Extension of University Teaching.

Johnson: a Psychological Study"; “Women's Work in Iowa"; “The Relations of Intemperance to Insanity"; “Relations of Intemperance to Heredity"; “Inebriety in Women", in two series; “Contributions to the Study of Epilepsy"; “The Use and Abuse of Narcotics"; “Heredity in Its Relation to Charity Work"; “Overcoming Evil Inheritance"; “The Press as a Factor in Reformatory Movements"; “Legal Protection For Girls"; “Earthquakes"; “The Relation of Academies of Science to the Community"; “Early History of the Iowa Orphan's Home"; “Occupations and Amusements for Insane Women"; “Provision for Feeble-Minded Children"; "Suicide in Its Relation to Mental Unsoundness"; “Child-Saving Work in the United States"; “Child-Saving Work in Foreign Fields", a series of twelve papers; "The Child and the State"; “The Utility of State Boards of Charity"; “Charity Organization in Cities"; “Health Talks", being a series of six annual talks to working girls and women of Davenport, under the auspices of the Lend-a-Hand Club, 1888–94; and “Emergency Lectures", two series of five lectures each to women on accidents or “What to Do Until the Doctor Comes", 1890.