This is a question that everyone should consider asking before giving to a charitable cause. Unlike some organizations that focus on international health, 3P works directly with a grassroots organization called the Haiti Medical Project, which is lead by and comprised almost entirely of Haitian citizens. We support many of their ongoing sustainability efforts and supplement their work with elements of preventative health. We are also run entirely by unpaid volunteers and work hard to be transparent about how every donated dollar is spent.
For more thoughts on this topic, please see the blog post Fighting Voluntourism with Sustainability.