The ship's doctor during the second season.
Katherine Pulaski is the chief medical officer of the Enterprise-D for the second season of The Next Generation, filling the post while Beverly Crusher heads Starfleet Medical. She is blunt and opinionated, prefers traditional medicine, distrusts the transporter, and once had a relationship with Riker's father Kyle.
At first she treats Data as a machine, mispronouncing his name and doubting his abilities, but she gradually learns to respect him. She also earns Worf's trust by keeping an embarrassing childhood illness of his confidential.
In Unnatural Selection she is exposed to a disease spread by genetically engineered children at a research station and begins to age rapidly. The crew save her by running her through the transporter with a sample of her own DNA to restore her original pattern, so the technology she distrusts saves her life. Crusher returns in the third season and Pulaski leaves the series.