Background. Total knee arthroplasty (TKA) is a well-established procedure for end-stage arthritis of the knee with complications such as swelling and pain. The aim of this study is to estimate the effect of mirabilite with ice pack versus ice pack in relieving pain, swelling, range of motion (ROM), and serum CRP level on patients after TKA. Methods. Eighty patients undergoing primary unilateral TKA were randomly assigned to two groups (MIP group and WIP group). We used VAS to measure knee pain at 24 h, 48 h, and 72 h after the surgery, respectively. Knee swelling degree was evaluated by measuring the girth of the leg at the center of the patella and 10 cm above and below it at the same frequency. The active ROM of the knee was measured by using a universal goniometer of plastic material at 72 h postoperatively. The serum CRP level was also measured at 72 h postoperatively. Results. The MIP group showed statistically significant lower knee girth at 48 h (
p
<
0.05
) and 72 h (
p
<
0.05
) postoperatively and VAS score at 72 h (
p
=
0.018
) postoperatively after TKA than the WIP group. The ROM of the MIP group was significantly wider than the WIP group (
p
=
0.024
). The CRP level (
p
=
0.036
) and length of stay (LOS) (
p
=
0.037
) of the MIP group were significantly lower than the WIP group. Conclusion. Mirabilite with ice pack after TKA showed superiority in relieving pain, reducing swelling, and improving ROM than ice pack only.