Yard or Patio
Be aware that whether you are welcoming home a Chi puppy or an adult, the Chihuahua is a close-to-the-ground kind of dog. For this reason, the breed is particularly susceptible to contact with chemicals, plants, insects, and animals that can be found in your yard.
As the king of lizard chasers, the lion-hearted Chihuahua cannot resist the urge to chase and kill small, moving creatures. Normally this prey drive translates to a few insect body parts or a lizard tail gracing your kitchen floor now and then. Depending on where you live, however, contact with certain types of toads, insects, spiders, snakes, and scorpions could prove deadly to your Chihuahua.
Items that are commonly used in the garden or patio that are dangerous to dogs include citronella candles, fly baits containing methomyl, and slug and snail baits containing metaldehyde. Do you have a small pond in your yard? The blue-green algae that grows in smaller bodies of water is toxic. What about a compost pile that you're waiting to work into your vegetable garden or cocoa mulch spread in your carefully groomed flowerbeds? These are toxic, too.
Many plants, shrubs, and even trees are highly toxic to dogs. (For instance, all parts of the cherry tree are poisonous.) If you have a Chi who likes to explore and chew, either remove these plants from your garden or devise a way to block your Chihuahua's access to them.
If you have any questions regarding a particular plant you are considering adding to your yard or one that is already there, you can check the ASPCA Web site, which maintains an alphabetical list of toxic plants.