We have heard that the Medical Medium recommends this and, even though the bottle says that it should be diluted, there's no reason to do this.
The reason we encourage people to dilute is that Zinc can cause nausea and stomach cramps in some people (this is the same with all liquid Zinc products).
If you plan to take your ionic Zinc without dilution, it's good to ensure you have at least a little food in your stomach to help to guard against nausea and stomach cramps.