The present invention provides antimicrobial peptides that exhibit a broad range of antimicrobial activity to gram positive and gram negative bacteria, as well as fungi, mold, and virus. The antimicrobial peptide of the invention is a cationic peptide, and may contain an HIV-TAT or reverse HIV-TAT sequence, or derivative thereof. The present invention further provides antimicrobial compositions containing the cationic peptide. Such compositions are especially useful for topical application to the skin, hair, nail, vagina, urethra, ear, oral cavity, nasal passage, respiratory system, opthalmic region, and various mucosal regions. The compositions of the present invention improve the condition and/or appearance of the treated region, and are suited for long-term and/or routine use to, for example, prevent or prevent the recurrence of microbial infection. The present invention further provides kits for use in improving the condition or appearance of skin, nail, or treated area. These kits may facilitate ease of use, long-term storage, and/or efficacy of the compositions.