Disposing of trash down drains and toilets can lead to sewer overflows and backups that can cause harm to human health and our local environment. Just because the package says "flushable" does not mean that it should be flushed. Many items marketed as disposable or flushable do not degrade like toilet tissue and often times clog pipes, tangle pumps, and cause messy sewer backups into homes, businesses, and streets.
The sewer system is designed to dispose of very specific items. Using your toilet for disposal of many modern products will often result in blockages. The drains that connect your home to the sewer main are only big enough to carry water, toilet paper, and human waste. These drains are often no wider than 4 inches in diameter.