Dr. Pitcairn graduated with a BS & DVM degrees from the University of California, Davis, in 1965. Entering private practice in Southern California, he worked with both small animals, farm livestock and zoo animals.
In 1967, he accepted a position at Washington State University, Pullman, Washington, as Assistant Professor. This was followed by full time attendance in graduate school with a major in microbiology and immunology and a minor in biochemistry, this work completed in 1972 with a PhD degree (WSU 1972).
Following this, Dr. Pitcairn worked as a faculty member at WSU, then re-entered private practice at a variety of clinics in Oregon and California, including a several years at the Monterey County SPCA, Monterey, California.
In 1982, the first edition, with his wife Susan, of Dr. Pitcairn's Complete Guide To Natural Health For Dogs and Cats was published. It is now in its third edition (2005).
In 1985, he moved to Eugene, Oregon, to establish the Animal Natural Health Center, a practice devoted solely to use of homeopathy and nutritional therapy.
In 1992, following several years of teaching workshops in homeopathy, the Professional Course in Veterinary Homeopathy was established for licensed veterinarians. This is a 130 hour classroom course which meets 5 times over the year and is accredited by the Academy of Veterinary Homeopathy. There are homework and case assignments. Completion of the course qualifies the student to enter certification process of the Academy of Veterinary Homeopathy. By 2009, 14 classes and over 450 veterinarians have been trained in homeopathic practice by Dr. Pitcairn. By 2009, Dr. Pitcairn has taught 125 four-day seminars in homeopathic medicine.
In 1995, Dr. Pitcairn co-founded the Academy of Veterinary Homeopathy, the first professional organization of practicing veterinary homeopaths in the United States.
In 2006, Dr. Pitcairn retired from a full practice and moved to Sedona, Arizona and established the ANHC Education Programs, dedicated to educating veterinarians in the proper use of homeopathy in clinical practice. He continues to be active in teaching, consulting and writing in the area of homeopathic medicine and healing of disease.