For the first time, a UK feminine hygiene company has shown a pad absorbing red — not blue — "period blood" in an advertisement.
A woman in the shower with blood running down her leg is also shown in the ad, with Bodyform saying it hoped it would help confront "period taboos".
In a post on Twitter, the company said:
"Women don't bleed blue liquid, they bleed blood.
"Periods are normal. Showing them should be too."
Bodyform said an online survey it conducted found 74 per cent of men and women wanted to see a "more realistic representation of periods in advertisements".
Dr Elizabeth Farrell, a gynaecologist and medical director of Jean Hailes for Women's Health, said any campaign that acknowledges a woman's normal biology is positive.
"Menstruation is a normal part of being a woman, but no-one talks about it," Dr Farrell said.
"It's considered so negatively in so many cultures.
"It's timely to show realistically what is a monthly reality for all women during their reproductive years."
Many took to social media to respond to the realistic portrayal, saying, "It's about bloody time".
"Bravo to Bodyform for finally being honest about menstruation. I might even stop banging on about the blue juice now," one person wrote on Twitter.
Another wrote: "This may seem like a minor change, but it's a massive step forward and it makes me very happy! Nice work."
However, it was not all praise.
Some complained about the sight of blood, which can make people feel ill or faint.
"I don't agree with the campaign … we all know what sanitary products are used for. We don't need visuals thanks very much," one person wrote.
Another wrote: "I hate blood. Makes me feel ill."
Last year, another ad for Bodyform was praised for stamping out menstrual taboos by focusing on women's ability to push past their physical limits during exercise.