ITV has received 60 complaints over the latest episode of costume drama Downton Abbey, broadcast on Sunday.
Viewers took to Twitter to express their "shock" and "distress" after Anna May Bates (Joanne Froggatt) was attacked and raped by a guest's valet.
A warning alerting viewers to the upsetting scenes was broadcast before the episode aired.
Broadcasting watchdog Ofcom has also received a number of complaints - although it cannot yet release figures.
An average of 9.2 million viewers watched the episode, with a peak audience of 9.9 million.
They saw Anna attacked while the rest of the servants, guests and family were watching an opera performance upstairs.
Katy Rink writing in the The Daily Telegraph was one of those shocked at the episode. "Last night we writhed in our sofas, disbelieving and uncomfortable," she said, pointing out that the incident risked alienating viewers who watch Downton for gentle escapism.
Viewer Lucy Raine tweeted: "I am genuinely so distressed at what just happened on Downton Abbey I feel sick."
While Jennifer Durie tweeted: "I don't think I will ever forgive the writers of Downton Abbey for what they did to Anna."
The show has not been afraid to shock viewers in the past, with the unexpected death of key character Matthew Crawley bringing last year's Christmas episode to a sombre conclusion.