Published Nov. 12, 2013|Updated Nov. 12, 2013

I've been a humanitarian aid worker for a long time, and have even written a book about my experience. After a disaster like Typhoon Haiyan, I'm usually the person to whom friends and family members turn to ask, "How can I help?"

Unfortunately, well-meaning people repeatedly get it wrong. Updates have begun littering my Facebook wall from well-intentioned Americans: "On the way to local Filipino Market. With clothes and food ... Come on, go through your closets and make a stop at your market. They need food, detergent, canned goods, soap. They need flip flops. Any old shoes you don't want."

The responses are coming in: "Terrific idea. Making my way there now."

And another: "Good to know. Cleaning out my closet as I write this."

Americans are exceptionally generous in the wake of an emergency. After the 2010 earthquake in Haiti, Americans donated more than $1.4 billion to relief and recovery efforts; they donated $1.6 billion after the 2004 South Asian tsunami. But often these very humane instincts - to help people after a massive disaster - result in inappropriate donations that can actually do much more harm than good. Here's why.

After the tsunami, similarly well-intentioned people cleaned out their closets, sending boxes of "any old shoes" and other clothing to the countries. I was there after the tsunami and saw what happened to these clothes: Heaps of them were left on the side of the road. Cattle began picking at them and getting sick. Civil servants diverted their limited time to eliminate the unwanted clothes. Sri Lankans and Indonesians found it degrading to be shipped hand-me-downs.

I remember a local colleague sighed as we passed the heaps of clothing on the sides of the road and said "I know people mean well, but we're not beggars." Boxes filled with Santa costumes, 4-inch high heels, and cocktail dresses landed in tsunami-affected areas. In some places, open tubes of Neosporin, Preparation H and Viagra showed up. The aid community has coined a term for these items that get shipped from people's closets and medicine cabinets as SWEDOW - Stuff We Don't Want.

Right now, access to people affected by the disaster is a major challenge facing the aid community in the Philippines. Roundtrip travel on the 7-mile road that connects the airport to the city of Tacloban currently takes about six hours; it is the only cleared road, according the United Nations. The airport's air traffic control and fuel storage facility were damaged. Consider what happens when plane full of unwanted donations is competing for runway space with planes carrying needed medicines and food items.

The good-hearted American response to disaster can border on the absurd. After the Haiti earthquake, American mothers pumped and donated hundreds of ounces of breast milk, meant for mothers who may have stopped lactating due to the trauma. I remember the response of the nutrition manager of the agency I was working for when the call came that the plane had arrived: "What am I supposed to do with this stuff now?"

Nutritionists specifically work to help mothers lactate again. If they are given supplementary breast milk, that supply will eventually run out and mothers will no longer be able to lactate. They'll typically end up feeding children foods they can't easily digest - like rice - or unclean water that will make the babies sick.

There is one simple way that people can help. Donate money - not teddy bears, not old shoes, not breast milk. Give money to organizations that have worked in the affected areas before the storm.Give money to agencies that are working with the government to ensure that their response is aligned with the national response.

Jessica Alexander is the author of "Chasing Chaos: My Decade In and Out of Humanitarian Aid." She is an adjunct professor at Columbia's Mailman School of Public Health and NYU's Wagner School of Public Service.

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