The present invention addresses the problem of providing a novel pharmaceutical composition that contains dorzolamide or a salt thereof and brimonidine or a salt thereof and exhibits a sufficient preservative effect. A pharmaceutical composition according to the present invention that contains dorzolamide or a salt thereof and brimonidine or a salt thereof has a pH of 6.0 or more. A pharmaceutical composition according to the present invention preferably does not include a preservative or includes a prescribed amount thereof, wherein said prescribed amount is preferably such that the logarithmic value of the ratio (B/A) of the number (B) of bacteria at the time of inoculation to the number (A) of bacteria when the number of viable bacteria is measured after inoculating bacteria in a test sample that comprises the preservative and water and mixing homogeneously such that the concentration of Escherichia Coli ATCC 8739 in the bacterial suspension is within the range of 105-106 cfu/mL, and collecting 1 mL of the test sample using a micropipette after the test sample has been stored for seven days at 20-25 °C while shielded from light, is 2.0 or less.
