Breast Cancer Awareness Month, one of the biggest fundraising events on the charity calendar, ended on Sunday amid hopes that it raised more than £10m.
But this year's event has been marked by growing concern about the link between the breast cancer charities that benefit and some of their corporate supporters.
The Women's Environmental Network launched a Think Before You Pink campaign alongside the month-long activities, questioning the safety of some of the companies' cosmetic products.
The network claims four supporters - Procter & Gamble, Avon, Boots and Estee Lauder, which developed the pink ribbon that symbolises the month - use products that may be linked to cancer.
"It's time to move on from raising awareness because people are well aware of cancer and need to start looking to prevent it," says Liz Sutton, the network's communications co-ordinator.
The network's Southampton and Waterside branch latched on to a Tickled Pink event at a local Asda store, which raised money for Breast Cancer Care, with its message.
The network's campaign leaflet states: "We are concerned that some companies claiming to support the 'fight' against breast cancer may be using or producing toxic chemicals that may increase the risk of developing the disease."
The charity urges supporters to send postcards to chief executives of the companies demanding that they remove phthalates and parabens from products, and reveal details of their financial connections with the charities involved in the awareness month.
All four companies denied that their products posed a cancer risk. An Avon spokeswoman said: "The cosmetics industry is well regulated and parabens and phthalates have a long history of safe use."
In a statement, Procter & Gamble said: "Cosmetic products containing parabens and diethyl phthalate do not pose a health risk to consumers."
A spokeswoman for Boots acknowledged there had been "considerable debate" about reports linking the products and cancer. But she added: "The value of these reports has been questioned, and they didn't prove there is a link with cancer." However, Helen Lynn, the network's health co-ordinator, contends that "lack of evidence does not mean no evidence".
Trade union Unison, which has been working with the network on environmental links with breast cancer since the mid-1990s, supports Think Before You Pink.
"We want a precautionary approach to suspected chemicals and more funding to focus on primary prevention of breast cancer," said Unison spokeswoman Jill Day.
Peter Reynolds, director of fundraising at Breakthrough, which hopes to surpass the £2.5m raised last year, said: "We agree with some of the things the network says, but there are some aspects we don't agree with."
Sangeeta Haindl, director of communications and marketing at Breast Cancer Campaign, denied Think Before You Pink had undermined the awareness month.