Introduction Arsenical keratosis is an important skin manifestation of chronic consumption of arsenic through drinking water. It appears either in both palms and/or soles. Presence of keratosis in palm is a social problem as it causes social stigma. In case of young unmarried girl it may even causes marriage related problems. There is no effective treatment for palmer arsenical kera -tosis still now. Soothing effect following topical applica -tion of salicylic acid (Islam et al., 2007) or propylene glycol (Dina and Misbahuddin, 2010) suggests the use in palmer arsenical keratosis. On the other hand, some of our foodstuffs have the capability to remove arsenic from the body. These include beta-carotene, retinol (Hall, 1946), spirulina (Fariduddin et al., 2001; Misbahuddin et al., 2006), spinach (Umar, 2007), corn (Chowdhury et al., 2009), etc. However, cessation of these drugs often recur the symptoms. These treatments may affect on patient’s adherence. Nigella sativa (Kala jerra) is an annual flowering plant belongs to the family Ranunculaceae. Its seeds used widely in all levels and religions in Asia, Middle East and Africa as herbal medicine, in religious purpose and for cooking. Because of possessing immense healing power, in Islam, theses seeds are regarded as a predic=- tive medicine. These seeds are also used as immune- modulatory (Salem, 2005), antimetastatic (Al-Jishi and Abuo Hozaifa, 2003), regulation of leukocyte phagocyte -sis (Haq et al., 1995), regulation of lipid peroxidation (Hosseinzadeh et al., 2007), antiasthmatic (Kanter, 2009; Boskabady et al., 2010) effects. N. sativa seeds are a good source of oil (essential oil and fixed oil), flavonoids, saponins, proteins, alkaloids, carbohydrates and mine- rals like potassium, phosphorus, sodium and iron while zinc, calcium, magnesium, manganese and copper were found at lower levels (Burits and Bucar, 2000; Al-Jassir, 1992). Though thymoquinone, superoxide anion scaven -ger is the main active element of the volatile oil, extracted from N. sativa seed (Burits and Bucar, 2000), A Journal of the Bangladesh Pharmacological Society (BDPS); www.bdps.info Bangladesh J Pharmacol 2014; 9: 15-21 Journal homepage: www.banglajol.info Abstracted/indexed in Academic Search Complete, Agroforestry Abstracts, Asia Journals Online, Bangladesh Journals Online, Biological Abstracts, BIOSIS Previews, CAB Abstracts, Current Abstracts, Directory of Open Access Journals, EMBASE/Excerpta Medica, Google Scholar, HINARI (WHO), International Pharmaceutical Abstracts, Open J-gate, Science Citation Index Expanded, SCOPUS and Social Sciences Citation Index ISSN: 1991-007X (Print); 1991-0088 (Online); DOI: 10.3329/bjp.v9i1.17167 Abstract This study was done to examine the role of Nigella sativa in 28 patients of palmer arsenical keratosis. Patients were randomized into two groups: Group A (n-15) receive capsules of placebo and vitamin E (200 mg) whereas Group B (n= 13) receive capsules of N. sativa oil (500 mg) and vitamin E (200 mg) orally for 8 weeks. The mean (± SD) clinical scoring of palmer arsenical keratosis in Group A before and after treatment was 99.3 ± 21.5 and 62.3 ± 14.3 respec- tively (37% reduction). On the other hand, in N. sativa oil treated group, the mean clinical score was 119.1 ± 20.3 before treatment which was reduced to 39.2 ± 8.4 (p<0.0001) after treatment (67% reduction). There were 65% reduc- tion of total arsenic in nail of Group A and 30% in Group B. In conclusion, oral administration of N. sativa oil improves the symptom of palmer arsenical keratosis as a result of reduction of body arsenic load. Article Info Received: 11 December 2013 Accepted: 17 January 2014 Available Online: 20 January 2014 Keywords: Arsenicosis Nigella sativa Palmer keratosis Number of Figures: 3 Number of Tables: 3 Number of Refs: 36 Correspondence: MM e-mail: mmisbah@bsmmu.edu.bd This work is licensed under a Creative Commons Attribution 3.0 License. You are free to copy, distribute and perform the work. You must attribute the work in the manner specified by the author or licensor. A double A double A double A double-blind, randomize, placebo blind, randomize, placebo blind, randomize, placebo blind, randomize, placebo-control trial to evaluate the control trial to evaluate the control trial to evaluate the control trial to evaluate the effect of effect of effect of effect of Nigella sativa Nigella sativa Nigella sativa Nigella sativa on palmer arsenical keratosis patients on palmer arsenical keratosis patients on palmer arsenical keratosis patients on palmer arsenical keratosis patients Tahmina Bashar 1 , Mir Misbahuddin 1 and Md. Amir Hossain 2 1 Division of Arsenic Research, Department of Pharmacology, Faculty of Basic Medical Science and Paraclinical Science, Bangabandhu Sheikh Mujib Medical University, Shahbag, Dhaka, Bangladesh; 2 Drug International Limited, Tongi, Dhaka, Bangladesh.