Accused axe murderer was "jovial" in the hours after his family members were slain.

A doctor who treated accused axe murderer, Henri van Breda, says the former Perth school boy was “jovial” after the alleged attack on his family.

Dr Michelle Van Zyl testified during the 22-year-old’s murder trial that she saw to him twice at the Vergelegen Mediclinic on January 27, 2015 – just hours after his parents and brother were slain in their Cape Town home.

The court heard that van Breda had initially presented to clinic voluntarily seeking treatment for a number of “superficial” lacerations, according to local news outlet News24.

Dr Van Zyl said the young man, who was accompanied by his sister’s ex-boyfriend James Reade-Jahn, appeared “confident, not emotional” and had the smell of alcohol on his breath.

His scratches were clipped, and he was discharged.

When he returned his demeanour had changed. Now he was in police custody, the primary suspect in the investigation into his family's murder.

"The second time, he wasn't so friendly and jovial, like when I saw him the first time," Dr Van Zyl told Western Cape High Court according to News24.

Van Breda stands accused murdering his parents Martin, 54, and Teresa, 55, and brother Rudi, 22, with an axe and attempting to murder his younger sister Marli at their upscale Stellenbosch estate.

He has pleaded not guilty, and instead claims he fought off a masked intruder then passed out following the attack on his family.

The trial continues before South Africa's Western Cape High Court.