Pearl Toy M.D. is an Internist who specialized in Hematology and Transfusion Medicine and is Professor Emeritus at the UCSF School of Medicine. Her work there from 1980-2022 included research, teaching, patient care and volunteer work.

Early on in 1981, she was director of the San Francisco Center, one of three centers of a study led by Cladd Stevens MD to determine the efficacy and safety of the hepatitis B virus (HBV) vaccine; the successful results led to FDA approval of the vaccines that safely prevented transmission of HBV from infected mother to child. In the AIDS era, she was Director of the American Red Cross in San Jose, CA (1983-84) where she installed some preventive measures to somewhat protect the safety of the blood supply prior to the availability of HIV testing. She also promoted the practice of patients donating their own blood for elective surgery. In 2003-5, she was Chair of the NIH committee on Transfusion-Related Acute Lung Injury (TRALI), the #1 cause of death from transfusion at that time. To investigate the causes and a prevention method, she was Principal Investigator of the NIH supported two-center TRALI study at UCSF and Mayo Clinic.

She graduated with honors from Smith College (Phi Beta Kappa) and the Stanford School of Medicine (Alpha Omega Alpha). Other honors include the Smith College Medal, UCSF Distinguished Teaching Award, the California Blood Bank Systems Award and the International Woman in Transfusion Medicine Award. She was invited to speak at the inaugural Margot Kruskall Lecture series at Harvard Medical School.