Wearing red colored clothing:
Red colored clothing is forbidden to be worn [by either men or women], as they are worn by gentiles for purposes of promiscuity, [and one who wears it transgresses the prohibition of “Thou shall not go in their statutes”]. It is likewise not befitting for modest people to wear red. [This especially applies to women, as red is a seductive color which attracts the eye of the male and leads to sin.] Furthermore, there is a tradition from our ancestors to avoid wearing red colored clothing. [However, some Poskim are lenient today to permit men to wear red colored clothing, as it is no longer a color that is worn by gentiles, and thus is no longer included in the prohibition of “Thou shall not go in their statutes”. Practically, one is to be stringent in this matter. This especially applies towards women, due to reasons of Tzenius, and so was the custom in all Frum Jewish homes, to avoid wearing any red colored clothing.]
What is wrong with the color red?
Despite what we may think, colors effect our feelings and attraction. Red is a color associated with blood, and is therefore the color of Eisav and Edom, of whom the verse states “By your sword you shall live.” A Jew who wears this color is spiritually effected by it. Furthermore, red represents love, romance and promiscuity, and naturally draws the attention of the male eye. This is referred to as the red dress effect. Studies and social experiments performed by universities and journalists have proven that the color red attracts the eye of a man more than other colors, and can be viewed as promiscuous even by women. In one study, it was found that the vast majority of wives would not allow their husbands to chat with a woman wearing a red dress, as opposed to if the same woman was wearing another color. In another study, it was found that men who dated women who wore red felt a more promiscuous atmosphere by the date, as opposed to if the same woman wore another color. The color red shouts for attention from the onlooker, and is thus avoided by the Jewish people who are traditionally modest and avoid wearing things that seek attention of others.
 See Michaber Y.D. 178/1; Maharik Shoresh 88; Igros Moshe Y.D. 1/81; Dibros Eliyahu 34
 Rama Y.D. 178/1; Beis Yosef 178; Maharik Shoresh 88; Aruch on Brachos 20a
 Aruch ibid; Rashi on the verse [Bereishis 49/11] “Ubidam Anavim Susa” that “Clothing which are colored with the blood of grape are worn by women to seduce the male, and is therefore called Susa by the verse”; Dibros Eliyahu 34
 Shach 178/3; Maharik ibid; See Drashos Chasam Sofer 2/244
The reason: See below for the discussion of “What is wrong with the color red”
 Darkei Teshuvah 178/16 in name of Rav Yitzchak Elchonan of Kovna; Orchos Rabbeinu that so ruled Rav Kanievsky even regarding women; Dibros Eliyahu 34 regarding men; See Igros Moshe Y.D. 1/81 based on Maharik ibid that red clothing is considered “Nidnud Peritzus” and hence may not be worn due to Chukos Hagoyim so long as Jews avoid wearing it. Thus, we see its dependent not on whether the gentiles actually wear it, but on whether Jews avoid wearing it or not.
 See Shach ibid that aside for Chukos Hagoyim, we have a tradition not to wear it, and hence why should the tradition stop simply because Chukos Hagoyim is no longer applicable; See Igros Moshe ibid; So rules Rav Eliezer Milameid and Poskim brought in next footnote [although most only discuss women and not men]
 Shevet Halevi 6/24-2; Beir Moshe 4/147 “Such clothing, such as a red skirt or blouse, are an abomination, and such clothing cannot be found amongst G-d fearing Jews.”; The Chasam Sofer did not allow any red clothing into his home; See Drashos Chasma Sofer 2/244; Rav SZ”A, and Rav Chaim Kanievsky, brought in Malbushei Kavod ibid; Halichos Bas Yisrael 7 footnote 7 in name of Rav Elyashiv; Teshuvos Vehanhagos 1/136; Dibros Eliyahu 34
 See Drashos Chasma Sofer 2/244 in name of Rabbeinu Bechayeh that red draws down the power of Maadim, which is detrimental for a Jew
 Aruch ibid; Rashi on the verse [Bereishis 49/11] “Ubidam Anavim Susa” that “Clothing which are colored with the blood of grape are worn by women to seduce the male, and is therefore called Susa by the verse”; For a secular study on this matter-see here http://www.sciencemag.org/news/2012/02/red-dress-effect [This site was viewed by us with a filter which prevents potential immodest pictures, which may or may not be on this page. You can avoid immodest pictures from showing up by attaching a filter to your internet, and/or disabling your browser from showing pics. In general, every G-d fearing Jew must have some filtering system and/or picture blocking method installed onto his internet, to allow for Kosher internet access.]