• Erythema score and other local and non-local adverse events [ Time Frame: After treatment ] [ Designated as safety issue: Yes ]
• The reduction in inflammatory lesion counts from baseline [ Time Frame: 4 weeks after last treatment ] [ Designated as safety issue: No ]
• The reduction in noninflammatory lesion counts from baseline [ Time Frame: 4 weeks after last treatment ] [ Designated as safety issue: No ]

In this multicenter study, patients with dark skin and acne vulgaris will be included. The patients will receive treatment with MAL PDT and placebo PDT.

• Experimental: PDT using MAL crem
• Placebo Comparator: PDT using Placebo cream

Inclusion Criteria:

1. Female and male patients, age 15 to 40 years with acne vulgaris.
2. Patients with skin type V or VI (Fitzpatrick).
3. Patients with two areas of each 8x8 cm2 on the back that include at least 5 inflammatory lesions (papules, pustules, and nodules) each. The minimum distance between the two areas should be at least 4 cm.
4. Patients with no more than 2 nodular lesions in any of the two areas of each 8x8 cm2 on the back.
5. Patients who are surgically sterile, postmenopausal, abstinent, or willing to use an adequate means of contraception including birth control pills, or barrier methods and spermicide for at least 14 days prior to Day 0. Patients using birth control pills must have used the same product and dose for at least 3 months and must agree to stay with the same product and dose for an additional 3 months.
6. Patients must be willing and capable of following study instructions to the extent and degree required by the protocol.
7. Patients must sign the approved informed consent form prior to any study procedures.
8. Patients must be willing to be photographed. Patients must be willing to sign a photography consent form.

Exclusion Criteria:

1. Known allergy to MAL, to a similar PDT compound, or to excipients of the cream.
2. Participation in other clinical studies either concurrently or within the last 30 days.
3. Patients who have a condition or who are in a situation, which, in the investigator's opinion, may put the patient at risk, may confound the study results, or may interfere with the patient's participation in the study.
4. Clinically significant sensitivity to visible light, or has porphyria or porphyrin sensitivity.
5. Exposure to ultraviolet radiation (UVB phototherapy) within the last 30 days.
6. Patients with a washout period for topical treatments for their acne in the two treatment areas of less than 14 days. Any topical treatment on the face or other areas outside the two treatment areas will be allowed.
7. Patients with a washout period for oral antibiotics for treatment of their acne of less than 1 month.
8. Patients with a washout period for oral isotretinoin of less than 6 months.