Eighteen one-humped she-camels were divided randomly into three equal groups: group 1 served as control; group 2 (MGA) received (0.5 mg/ head/day) of Melengestrol acetate for 10 days and; group 3 (CIDR) were fitted intravaginally with controlled internal drug release (CIDR, 1.38g P 4) for 10 days. At day 10 the MGA and CIDR groups were administered PGF 2α and 3000 IU PMSG, MGA feeding was withdrawn and CIDRs were removed. Animals were given 5000 IU of hCG 10 days later and were artificially inseminated (day 20). Blood samples were collected from all groups at day 0 = day of CIDR insertion and beginning of MGA feeding; day 5 = 5 days after CIDR insertion and onset of MGA feeding; day 10 = day of CIDR removal and MGA feeding withdrawal; and day 20 = day of hCG injection. Serum biochemical and mineral constituents, and serum reproductive hormones (estradiol-17β and progesterone) were determined. Overall means of serum concentrations of total protein, albumin, cholesterol, and AST enzyme were not different among treatments. Treatment with CIDR increased BUN at days 10 and 20 and the overall mean BUN concentration compared to control and MGA groups. Treatments with CIDR and MGA numerically increased serum glucose compared to control at days 10 and 20. However, overall mean serum concentrations of HDL were not affected by CIDR and treatments. In the meantime, CIDR and MGA increased serum ALT concentrations at days 20 and the overall means ALT concentrations compared to control. No marked changes were detected in serum concentrations of Ca ++ and Na + in the MGA and CIDR groups compared to controls. Serum concentrations of K + were increased at day 20 in the MGA and CIDR groups than at days 0 and 5. Overall mean serum concentration of K + was greater in the CIDR group (4.2 ± 0.14 mEq/l) than in control (3.4 ± 0.16 mEq/l) and MGA (3.5 ± 0.14 mEq/l) groups. Similar trend was detected in serum concentrations of P as MGA and CIDR groups had more (P < 0.01) serum P (4.7 ± 0.36 and 4.6 ± 0.24 mg/dl) at days 20 compared to days 0, 5 and 10. Results also indicated that natural progestin treatment (CIDR) increased P 4 concentration at days 5 and 10 while control and MGA-fed animals had lower P 4 levels. Also, CIDR increased the overall mean P 4 concentration (2.9 ± 0.28 ng/ml) compared to control and MGA groups (0.5 ± 0.33 and 0.9 ± 0.29 ng/ml). Both MGA and CIDR groups had lower estradiol at days 5 and 10. At day 20, estradiol was elevated in the CIDR group compared to control and MGA groups. In conclusion, progestin treatments exerted no deleterious effects on animal health and can be used without limitation for further treatments. Natural P 4 improved the pattern of reproductive hormones secretion without detrimental effects on animal health and blood biochemical constituents.