PLA (polylactic acid) is a bio-based plastic usually made from corn or sugarcane. It's most common applications to date are in food packaging (clam shell containers and liquid bottles), table ware (cups, plates and cutlery), and even in medical devices. While there is some controversy over the trade-offs of using a material primarily derived from food, and over the potential of PLA to compromise material streams in the existing plastics recycling infrastructure, PLA is generally considered a good sustainable substitute for conventional plastics.
Eco-Pro: Made from renewable resources and compostable (in an industrial composting facility), PLA can reduce dependence on oil for materials manufacturing and help reduce the size of landfills.
Eco-Con: Some argue that the production of PLA can lead to monoculture and increases in GMO corm production, both of which have adverse biological effects
Question the Premise of the Material: Where and how will the product be disposed of? If there is no access to industrial composting, maybe the better choice is to use a durable, recyclable plastic, like polypropylene.