The use of hygienic towels and sanitary pads creates a large amount of waste. On average, a woman may use around 17,000 sanitary products in her lifetime, resulting in between 100 and 150 kilograms of waste. Globally, this adds up to about 7 billion tampons and 12 billion sanitary pads, which can take nearly 500 years to break down. As a more sustainable option, menstrual underwear—a reusable product designed to absorb menstrual flow—is gaining popularity. Experts suggest that these products are best suited for women with light to normal menstrual flow, while specialized "night" models with double layers can offer protection for up to 6 to 8 hours. Toxic shock syndrome (TSS) is a rare but serious condition that has seen an increase in France since the 2000s, rising from 5 cases in 2004 to about 20 cases annually. Despite this increase, the number of cases remains very low compared to the number of women who menstruate each month. Dr. Odile Bagot, a gynecologist, explains that TSS is often linked to the use of tampons, but it can also occur with menstrual cups. Since April 2024, a new decree requires manufacturers of feminine hygiene products to include detailed information about their composition, usage, precautions, and potential side effects, including TSS, on product packaging. Menstrual underwear is typically made from materials like cotton (including organic), bamboo, and nylon, and is available in a range of sizes from XS to XXL. These products can absorb as much as two tampons of heavy flow. Sokona Martin recommends soaking the underwear in cold water and rinsing until the water runs clear before washing them by hand with a degreasing soap. It is advised to avoid soaps rich in glycerin, such as Marseille soap, which can block the absorbent fibers. Air drying is preferable to maintain the fabric's quality. Dr. Bagot suggests washing the underwear in a machine at least at 40 °C after thorough rinsing. Several brands now offer menstrual underwear, including So Cup, which provides models made in France in sizes from XXS to XXL. These products feature an impermeable bottom, an absorbent layer made from natural bamboo fiber, and an antimicrobial polyester layer. Louloucup offers a range from XS to XXL, certified by Oeko Tex, with an absorption capacity equivalent to three tampons. Blooming menstrual underwear is available at supermarkets such as Auchan and Monoprix, with sizes ranging from 36 to 44 and made from various materials. Modibodi offers swimsuits with a 3 mm absorbent lining for young girls, suitable for ages 8/10 to 14/16 years. Starting in September 2026, reusable hygiene products such as menstrual cups or menstrual underwear will be partially reimbursed by the French Social Security system at 60% for women under the age of 26, or for those who qualify for the solidarity health supplement, regardless of age. This change is expected to affect approximately 6.7 million women, who will need to visit a pharmacy to claim the reimbursement.