38 CFR § 3.300 - Claims based on the effects of tobacco products.
(a) For claims received by VA after June 9, 1998, a disability or death will not be considered service-connected on the basis that it resulted from injury or disease attributable to the veteran's use of tobacco products during service. For the purpose of this section, the term “tobacco products” means cigars, cigarettes, smokeless tobacco, pipe tobacco, and roll-your-own tobacco.
(b) The provisions of paragraph (a) of this section do not prohibit service connection if:
(1) The disability or death resulted from a disease or injury that is otherwise shown to have been incurred or aggravated during service. For purposes of this section, “otherwise shown” means that the disability or death can be service-connected on some basis other than the veteran's use of tobacco products during service, or that the disability became manifest or death occurred during service; or
(2) The disability or death resulted from a disease or injury that appeared to the required degree of disability within any applicable presumptive period under §§ 3.307, 3.309, 3.313, or 3.316; or
(3) Secondary service connection is established for ischemic heart disease or other cardiovascular disease under § 3.310(b).
(c) For claims for secondary service connection received by VA after June 9, 1998, a disability that is proximately due to or the result of an injury or disease previously service-connected on the basis that it is attributable to the veteran's use of tobacco products during service will not be service-connected under § 3.310(a).